1. Field of the Invention
The invention relates to image processing apparatus and method and recording medium for realizing a color matching between a light source color and a material color.
2. Related Background Art
FIG. 2 shows a prior art of an image signal processing apparatus for performing a signal conversion between a signal of a light source color and a signal of a material color (body color). The light source color is a color of a light which is emitted from a light source. The material color is a color of a material which reflects or transmits the light. In the apparatus, input color signals obtained from an image input unit 201 are corrected by a color correction unit 202 and the correction data is sent to an image output unit 207. A signal conversion is performed by an equipment characteristic conversion circuit 203 by using the signal from the image input unit 201 and an input equipment characteristic read out from an ROM 205. The corrected signals are further converted into output color signals by using an output equipment characteristic read out from an ROM 206.
As mentioned above, in the conventional color correction unit, when the material color and the light source color are matched, no correction is performed with respect to a luminance component of the material color.
However, when the human being recognizes the light source color and the material color as a same color, if each color tag is actually measured by a method according to the JIS, luminance values of both of those colors are fairly different. Therefore, there is a problem such that the light source color and the material color are seen as different colors when the conventional color signal correcting method is merely used for the data conversion between the light source color and the material color.
As a method of color matching even when color modes are different, the applicant of the present invention has proposed, for example, a method of calculating white as a reference of a perception of the human being on the basis of an observation light source and a ratio adapted to a monitor and converting an image on the basis of such calculated white as a reference or the like.
As shown in FIG. 3, a chromaticity value of white serving as such a perception reference is calculated from the observation light source, a chromaticity (for example, CIEx,y chromaticity value) indicative of a color tone of white of the monitor, and an adaptation ratio. On the other hand, as a luminance value, a value calculated by a color matching experiment, a proper value obtained by a simple preparatory experiment, or a value that is equivalent to the luminance obtained by a color measurement is used.
The applicant of the present invention also has already proposed a method whereby when a luminance value of a light source by which a printed matter is seen is very brighter than a display limit luminance of a monitor, an image is displayed on the monitor by using a value lower than the luminance data derived by measuring the printed matter, thereby matching both colors.
Even when the color modes differ, in order to enable both colors to be seen as a matched color, it is necessary for the human being to clarify the relation between both of the color tones and brightness senses of both colors to be matched.
As mentioned above, however, although the relation has been clarified with respect to the chromaticity values, as for the luminance, a value obtained by a color matching experiment is used or the like and the relation about the luminance is not yet clarified. As mentioned above, the value calculated from the color matching experiment can be applied in only a certain limited environment. When the human being wants to observe in an environment different from the environment in which the experiment was performed, parameters have to be obtained by executing color matching experiments or the like, so that there is still room for improvement about a drawback such that a generality extremely lacks.
Further, it is known that when the luminance of the printed matter is very higher than that of the monitor as mentioned in the proposed technique, the color matching can be performed by outputting a value lower than the luminance of the printed matter to the monitor. However, the relation about to which extent the luminance is reduced when the luminance of the printed matter has what degree of value is not yet clarified. Further, when the luminance of the printed matter is lower than the luminance of the monitor, whether such a relation is held or not cannot be known.
As mentioned above, in case of performing a color matching even when the color modes of the light source color and the material color are different, the relation of the luminance when the light source color and the material color are matched is hardly clarified yet.
It is an object of the invention to highly accurately realize a color matching between a light source color and a material color.
To accomplish the above object, according to the invention, there is provided an image processing method whereby when a display of a light source color to display a visible image by a color generation and a display of a material color to display a visible image by depositing a coloring agent onto a material to be recorded are color matched, a luminance component of the material color display is corrected so as to be larger than the luminance component of the light source color display.
To accomplish the above object, according to the invention, there is also provided an image processing apparatus for matching display colors in both of a display apparatus of a light source color to display a visible image by performing a color generation and a display apparatus of a material color to display a visible image by depositing a coloring agent onto a material to be recorded by using those display apparatuses, wherein the image processing apparatus has correcting means for correcting the luminance component of the display image by the material color display apparatus so as to be larger than the luminance component of the display image by the light source color display apparatus.
Another object of the invention is to provide image processing method and apparatus such that when a color matching between colors of input and output images is performed, on the basis of information regarding a light source in a display apparatus, a deviation of colors to be seen which is caused due to the relation between the light source and the display apparatus is corrected, and in order to correct a deviation of the colors to be seen which is caused due to a difference of the color temperatures between the light sources of the input and output images, such a deviation can be corrected on the basis of information of each light source.
To accomplish the above object, according to the invention, there is provided an image processing apparatus for performing a color matching between colors of input and output images, comprising: first correcting means for correcting a deviation of colors to be seen which is caused due to the relation between a light source and a display apparatus on the basis of information regarding the light source in the display apparatus; and second correcting means for correcting a deviation of colors to be seen which is caused due to a difference of the color temperatures between the light sources of the input and output images on the basis of the information of the light sources.
Still another object of the invention is to provide image processing method and apparatus such that when a color matching between colors of input and output images is performed, a deviation of colors which is caused due to a difference of the modes between a material color and a light source color is corrected, and in order to correct a deviation of colors to be seen which is caused due to a difference of the color temperatures between the light sources of the input and output images, such a deviation can be corrected on the basis of information of the light sources.
To accomplish the above object, according to the invention, there is provided an image processing apparatus for performing a color matching between colors of input and output images, comprising: first correcting means for correcting a deviation of colors which is caused due to a difference of the modes between a material color and a light source color; and second correcting means for correcting a deviation of colors to be seen which is caused due to a difference of the color temperatures between the light sources of the input and output images on the basis of information of the light sources.
Further another object of the invention is to provide a method whereby in order to perform a color matching even when color modes are different, a relation between luminances of both of a material color and a light source color to be color matched by the human being is shown, thereby enabling a color matching to be performed even when the color modes differ.
To accomplish the above object, according to the invention, there is provided an image processing apparatus for performing an image process so as to visually match a light source color with a material color, comprising: input means for inputting image data regarding the material color; and converting means for converting the image data regarding the material color into image data regarding the light source color, wherein the converting means performs a conversion process so as to satisfy a relation shown by a curve which monotonously increases and is convex upward on a coordinates plane in which a luminance of the material color is set to an axis of abscissa and a luminance of the light source color is set to an axis of ordinate.
To accomplish the above object, according to the invention, there is provided an image processing apparatus for performing an image process so as to visually match a material color with a light source color, comprising: input means for inputting image data regarding the light source color; and converting means for converting the image data regarding the light source color into image data regarding the material color, wherein said converting means executes a conversion process so as to satisfy a relation shown by a curve which monotonously increases and is convex upward on a coordinates plane in which a luminance of the material color is set to an axis of abscissa and a luminance of the light source color is set to an axis of ordinate.
To accomplish the above object, according to the invention, there is provided an image processing method for performing an image process so as to visually match a material color and a light source color, comprising the steps of: inputting information regarding an observation light source; calculating a luminance component in perception reference white information on the basis of the information regarding the observation light source; calculating a chromaticity component in the perception reference white information by using a color adaptation ratio according to the information regarding the observation light source; and performing a color adaptation conversion process to image data on the basis of the calculated perception reference white information.